Edwin H. Colbert had already made his mark as a working paleontologist (discovering the early dinosaurs Coelophysis and Staurikosaurus, among others) when he made his most influential discovery: a skeleton of the mammal-like reptile Lystrosaurus in Antarctica, which proved that Africa and the southern continent used to be joined in one gigantic land mass. Since then, the theory of continental drift during the Mesozoic Era has done much to advance our understanding of dinosaur evolution.In 1969, just before retiring from the American Museum of Natural History in New York, Dr. Colbert traveled to Antarctica as part of a field expedition sponsored by the National Science Foundation.
While there, he was part of a team that discovered and identified a 220-million-year-old fossil of a Lystrosaurus, an early relative of mammals. Similar fossils had previously been found in South Africa. Since Lystrosaurus was not a swimmer, the discovery lent evidence to the theory that the present-day continents must have once been part of a large land mass or supercontinent that slowly separated over millions of years.
The continental drift theory, originally proposed in 1912 by Alfred Wegener, a German meteorologist, had long been debated by scientists, but the discovery was a crucial piece of evidence. Dr. Laurence M. Gould, the scientific leader of Adm. Richard E. Byrd's first expedition to Antarctica, in 1928, described the discovery in an article in The New York Times as ''one of the truly great fossil finds of all time.''